Blank for producing a dental prosthesis

ABSTRACT

A one-piece or multi-piece prosthesis blank for manufacturing a dental prosthesis. The blank is constructed from a gum-colored material and a tooth-colored material. It is characterized by being connected to each other at connecting surfaces, having an interface between the gum-colored and tooth-colored materials. This interface, when viewed along the connecting surfaces has an undulating shape and viewed in the vestibular direction has a radial shape. In order to finish the dental prosthesis, a CAD/CAM device determines the exact course of a gingival line, based on patient-specific data, and produces the prosthesis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a Continuation Application ofU.S. application Ser. No. 16/823,891, filed on Mar. 19, 2020, which is aDivisional Application of U.S. application Ser. No. 15/554,481, filed onAug. 30, 2017, which is the National Stage application of Internationalpatent application PCT/EP2016/054266 filed on Mar. 1, 2016, which claimspriority to European patent application No. 15157544.6 filed on Mar. 4,2015, all the disclosures of which are incorporated herein by referencein their entirety.

TECHNICAL FIELD

The invention relates to a blank for a dental prosthesis.

BACKGROUND

It has been known for long to construct prostheses, and also teeth, fromseveral layers.

It is referred to the solutions known from WO 90/13268 A1 and WO91/07141 A1 for examples thereof.

Based on these relatively old solutions, multi-layered plastic elementsproduced with the aid of CAD/CAM technology have been suggested recentlywhich serve to produce teeth and prostheses in order to provide forteeth and the prosthesis base to provide for a finished prosthesis. Dueto the different requirements to the various materials, namely thegum-colored prosthesis base material on the one hand and thetooth-colored tooth material on the other hand, this suggestion has notyet become established, even although it has become known otherwise toproduce teeth and a prosthesis base from PMMA.

Furthermore, rapid prototyping methods have been suggested recently,aiming to provide teeth and prosthesis bases from a plastic material—orpossibly from other materials, too. This development has not yetexperienced proper progress either up to now.

On the other hand, with respect to the increasing life expectancy thereis an increasing demand for full and partial prostheses, and for reasonsof simplicity the term prostheses comprises full as well as partialprostheses herein. This increasing demand is coupled with an alsoincreasing pressure on costs, already due to the considerably increasingdemand which is to be expected.

SUMMARY

Thus, the invention is based on the task of providing a prosthesisconstructed from a gum-colored material and a tooth-colored material,and a method of producing a dental prosthesis constructed from agum-colored material and a tooth-colored material, wherein theprosthesis can be produced cost-effectively and also offers considerablyimproved acceptance and is also optimized with regard to storagepossibilities

This task is inventively solved by claim 1. Advantageous furtherdevelopments may be taken from the subclaims.

It is provided with dental prostheses which are produced to be in onepiece or part in one embodiment, and in two pieces or parts in anotherembodiment, to connect the two materials with one another in a specialway. As viewed along the extension of the gingival arch of theprosthesis, the shape is wave-shaped, wherein the term wave-shaped alsoincludes an asymmetrical wave herein, that is to say a shape inwhich—similar to a catenary—small and narrow arches alternate with deepand wide arches.

A particular advantage is due to the fact that the wave shape of theprosthesis extends radially as viewed from a central point thereof.Thus, every wave trough and every wave crest extends on the same height,or in a modified embodiment on a straight line which may deviate fromthe horizontal by a few degrees, for instance by 10°, to the top or tothe bottom.

It is particularly favorable that the teeth of the gingival arch remainconnected to one another, but still appear to be individual teeth due tothe deep grooves between the teeth as viewed from the vestibulardirection. The reason for this is among others that particularly in theanterior tooth region light incident from the side casts shadows suchthat the interdental spaces are shadowed by at least one neighboringtooth, and in this respect the inventive multi-tooth arch may not bedifferentiated from individual teeth.

The gum-colored material and the tooth-colored material are intensivelyconnected to one another to produce the inventive two-coloredblank—either by a one-piece production, or by bonding or polymerizing.The one-piece and inseparable production can be achieved, for instance,in that the materials are pressed onto one another in a state which isstill soft—or even liquid—at the interface, such that they penetrateinto one another—when viewed through a microscope. However, with thistype of production, too, the transition area is in the submillimeterrange, for instance, as thick as less than 100 μm.

Even in layer polymerization there is such a transition area having thesame size, and in bonding processes the adhesive joint can have a lowthickness of, for instance, between 40 and 200 Preferably, the blank ofgum-colored material is at least partially shaped like a circular arc.The realization by means of a disc has proven to be particularlyfavorable, wherein, for instance, in a circular disc having a diameterof 98.5 mm two prosthesis bases may easily be accommodated. In the blankstate, the tooth-colored material of the blank has a size which islarger than a human dental arch, that is to say preferably larger than 8cm.

In the same manner the material input for the production of thetooth-colored blank may be optimized. In case of full prostheticdentistry, for instance, a circular disc having the same diameter canreceive a plurality of dental arches. It is possible, for instance, torealize two relatively large dental arches opposite from one another ina way known per se. In the case of lower jaw prostheses the arches canbe realized substantially as parabolas, and in the case of upper jawprostheses in the form of ellipses.

It is favorable that the wave crests of the tooth-colored material areprovided at tooth positions and the wave troughs at interdental spacepositions. In this way, after the finishing process, for instance by acommon milling process, the appearance will resemble the naturalgingival margin.

In this way, when the material is utilized ideally, for instance up tosix dental arches may be milled from a tooth-colored blank disc, whereinit is to be understood that in the realization of partial prosthesesthis number can even be increased considerably. It is also possible toattach a dental arch blank to the upper side of a gum-colored prosthesisblank, and a further one to the lower side thereof—offset by 180°—suchthat upper jaw and lower jaw prostheses may be produced in one go.

In a further advantageous embodiment it is provided to integrate areinforcement into the gum-colored prosthesis tooth carrier. It can, forinstance, consist of metal or of any other suitable material, whosestrength is larger than the strength of the gum-colored material. Thereinforcement may either be integrated in advance, that is to say, forinstance, in the gum-colored blank, or may be inserted, in particular,slid in, retrospectively by forming a pocket.

It is provided to connect the tooth-colored blank and the gum-coloredblank with one another intensively in the preferred embodiment—be it bypolymerizing or by bonding—and to carry out the required millingoperation in this state. This has the advantage that the millingoperations can take place considerably faster. Clamping is onlynecessary in the area of the gum-colored blank disc. Due to theintensive connection between the tooth-colored and the gum-colored blankand due to the positive-locking fit between them by means of thecombined wave shape and radial shape the strength of the connection isalso surprisingly sufficient for the milling operation and the forcesapplied thereat.

At the same time, this automatically tests the ability of the connectionto cope with strain in view of the shear forces during mastication whichwill be applied later.

Here, the dental arch shape of the tooth-colored mass is particularlyfavorable which is considerably superior to an alternative solutionhaving individual teeth in view of the strength of the connection.

According to the invention it is particularly favorable that theprosthesis—after having fixed the gum-colored and the tooth-coloredmaterial to one another—may be automatically finished by milling, inparticular in a CAD/CAM unit, involving the control device. The controldevice makes it possible to determine the exact position of thevestibular border line of the interface automatically and/or in auser-controlled way.

In an advantageous embodiment of the invention it is provided that thegum-colored prosthesis blank is provided with one to four substantiallysemicircular wave arches for receiving the tooth-colored material. Eachone of these wave arches has a radial character at the same time.

With a sophisticated arrangement, it is possible to produce at least twoprostheses, in particular also of different sizes, from one disc ofgum-colored material.

In a further embodiment it is provided that the interface—as viewed inthe vestibular direction—has a further, in particular less stronglydistinct wave line along its course.

Preferably, the exact course of the wave shape is adapted to thegingival line of the gingival margin of a human mouth. This holdsparticularly true for the anterior tooth region, while in the molarregion more strongly pronounced wave crests and wave troughs are evenpossible in order to further improve the positive-locking fit of theconnection.

In this respect, the inventive wave crests and wave troughs have a dualfunction:

On the one hand, by means of the positive-locking fit between the dentalarch and the prosthesis base the strength is improved considerably andin this respect bonding is supported which can be carried out by way ofthis example instead of by a polymerization process.

On the other hand the red/white transition can be represented easily inthis way, wherein it is to be understood that, in the finishedprosthesis, every tooth-colored wave crest follows the exposed edge ofthe tooth at its tooth neck with respect to the gingiva formed by thegum-colored material.

A CAD/CAM device finishes the dental prosthesis, according to theinvention, by determining the exact course of the gingival line, that isto say the vestibular border line of the interface as viewed from theocclusal direction, based on patient-specific data, and produces theprosthesis based thereon. In this way, the size of the prosthesis isdetermined in a patient-specific manner and different tooth arch shapescan also be accounted for, that is to say, for instance, slightlyrounder or slightly more triangle-shaped shapes.

Providing the necessary patient data is carried out as follows:

Either, an intraoral scan is initially carried out in a way known perse, or an impression is taken and then a 3D scan thereof also in a wayknown per se.

Anatomically relevant points are marked and serve as reference points.The software of the CAD/CAM device is supplied with the data obtained inthis way, and it automatically produces a suggestion for a prosthesis, aso-called virtual prosthesis, together with its control device. However,this prosthesis may be changed by the user, that is to say, forinstance, by the dental technician, at the CAD/CAM device.

For instance, the course of the gingival line—as viewed from theocclusal direction—may be adapted easily based on aesthetic aspects.

Here, the control device also takes into account the dimensions and thegeometry of the teeth, compared to the tooth arch blank and itsdimensions. When it becomes apparent that the desired tooth arch wouldnot fit into the blank, the software emits a corresponding alarm signal.

The same holds true for the prosthesis base blank which may also bereferred to as gingival blank. When the size of the prosthesis base islarger than that of the intended blank at one position, an alarm signalis also emitted indicating that the blank next in size is to be used.

If the desired shape has been determined virtually, the obtained data isreleased for further machining. In the case of a subtractive productionof the prosthesis, it is fed to a milling machine of the CAD/CAM deviceinto which a bicolored inventive blank with a wave-shaped/radialinterface is or will be clamped.

In the case of generative production, the data is fed to a rapidprototyping device in which the shape of the tooth arch blank and theprosthesis base blank is stored virtually with the inventiveradial/wave-shaped interface. Based on the obtained patient-specificdata and the design function of the CAD/CAM device the vestibular borderline of the interface is constructed, and then the prosthesis isproduced based thereon.

In any way, it is crucial that the tooth arch blank has an exactnegative shape of the surface of the prosthesis base blank at theinterface to the prosthesis base blank such that the two wave lineswhich extend radially fit to one another exactly and may be easilyconnected to one another intensively.

As a matter of fact, it is possible to produce, for instance, even fiveindividual parts and then to suitably join or combine them in accordancewith the requirements in order to provide the blank disc to thecustomer.

Then, the customer practically performs a milling operation from onesolid piece of material, that is to say the tooth material and thegingival material at the same time.

In a modified embodiment, it is provided to premodulate one of thematerials, for instance the prosthesis base, in view of the interfacetowards the tooth arch. In this embodiment, this radial wave shape isused as a base for casting without further ado, and then the tooth archis cast onto it using a corresponding mold and then fully polymerized.

In this solution, too, an exactly predefined wave line having thedesired gingival margin and a radial orientation with wave crests andwave troughs which become broader in the vestibular direction isproduced.

By means of the control device the individual tooth shape, and also therotation and the angulation of the teeth, and also the shape of theprosthesis base, may be determined based on the obtained patient datasuch that different designs of full prostheses may be produced.

The radial shape also ensures that, when the width increases—as viewedfrom the vestibular direction—the height of the teeth and wave crestsincreases at the same time. This corresponds to the anatomic conditions,as typically, when the tooth width increases, the dimensions of theteeth become larger in all three spatial directions such that a toothwhich is positioned more to the rear (as viewed in thelingual/vestibular direction) is also broader (as viewed in themesial/distal direction) and higher (as viewed in theocclusal-incisal/cervical direction) at the same time.

When the prosthesis base is present as a blank in the shape of a disc,it is preferred to insert semicircular wave arches into it. They serveto receive the tooth arches, wherein it is to be understood that thetooth arches have wave arches which match the wave arches of thegum-colored disc.

Surprisingly, it is possible in this way to provide aestheticallyparticularly well-made prostheses even with teeth of very differentsizes, wherein it is also possible, for instance with partialprostheses, to configure a small tooth arch from a tooth-colored blankon the one hand, and afterwards or simultaneously, for instance, a largetooth arch at another position.

Then, in this way, the large tooth arch is attached to a gum-coloredprosthesis base and the other tooth arch to another, also gum-coloredprosthesis base, and the gum-colored material and the tooth-coloredmaterial are joined to one another at the boundary layer.

The materials can be connected both by bonding and by polymerizing ontoone another, and due to the wave shape a positive-locking fit iseffected additionally which counteracts masticatory forces which act inparticular laterally.

Among the masticatory forces, the shear forces are particularly relevantwhich may amount to more than 1000N as is well known (see, for instance,the dissertation “Entwicklung and Anwendung einer Methode zurKaukraftmessung”, Tobias Fink, Charité Berlin 2007). In this connection,it is particularly favorable and increases the durability of theprosthesis to a surprising extent, that the positive-locking fit of theparts of the prosthesis stands the occurring alternating loads moreeasily.

In a modified embodiment, the teeth of the inventive prosthesis areconnected to one another via bridges made of tooth-colored materialwhich form the dental arch. In this way, compared to individual teeth,the lateral support against shear forces is improved by one order ofmagnitude.

By the way, this also holds true—albeit to a slightly smaller extent—forpartial prostheses which are subsumed under the term prosthesesaccording to the invention.

While individually produced and pre-fabricated teeth are typicallyreceived in tooth cavities in a prosthesis base which is producedaccording to prior art and are subjected to considerable shear stressdue to the leverage effect of the masticatory forces during mastication,the shear forces also heavily straining the adhesive surface, it isprovided inventively to absorb these shear forces over at least two wavecrests and wave troughs positively. The dreaded leverage effect of theindividual tooth with the leverage ratio of approximately 2:1 iseliminated as the dental arch provided in this way which comprises atleast two adjacent teeth in case of partial prostheses has aconsiderably larger width than height such that the leverage effect of2:1 is reduced to, for instance, 0.5:1.

It is to be understood that in case of complete dental arches which arerequired in case of full prostheses the respective leverage effect isreduced, for instance, to values of between 0.06:1 and 0.1:1, incorrespondence with the height/width ratio of the tooth-colored materialof the inventive prosthesis provided for each patient specifically.

In a modified embodiment, it is provided that the wave shape simulatesthe gingival margin as an interface between the materials. Of course, itis different from patient to patient, and it is particularly favorablein this respect that, with regard to the radial shape as viewed in thevestibular direction, the size, that is to say the width and the depthof the wave crests and wave troughs on the outside, that is to say onthe vestibular side of the dental arch, may be adapted to therequirements.

For this purpose, the inventive control device for producing theinventive prosthesis easily determines the radial position of the dentalarch—that is the position as viewed in the vestibular/palatal or lingualdirection—and produces the desired dental arch determined by CAD, forinstance, in a subtractive method together with the prosthesis base. Forinstance, this can be effected in a milling machine of the CAD/CAMdevice, as has been mentioned before.

The gum-colored and tooth-colored materials are connected with oneanother intensively, be it by adhesive bonding, be it by polymerizing oreven by producing them from one piece of material.

In case of a two-piece production it is favorable that both materialscan be connected to one another at any point in time and also in anyselection fitting one another.

Then, semicircular wave arch receptions ensure that the full circle ofthe disc is utilized ideally.

This applies to full prostheses, while smaller arch segments thansemicircular arch segments, that is to say, for instance, 60° segmentsor similar, can also be taken into account for partial prostheses suchthat a larger number of partial prostheses may be producedcost-effectively and quickly from one single gum-colored disc.

In case of a full prosthesis, it is also possible to ensure that thewave shape—as viewed along the gingival arch—does not extend exactlyhorizontally but to lower it slightly in correspondence with the naturalcourse of the teeth in the incisal area, for instance, by 1 mm, andaccordingly to raise it in the molar area to take account for the Curveof Spee and the Curve of Wilson.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, details and features may be taken from the followingdescription of several exemplary embodiments of the invention inconjunction with the drawings, in which:

FIG. 1 shows a schematic perspective view of a blank for producing adental prosthesis, namely a circular disc-shaped gum-colored blank;

FIG. 2 shows the illustration according to FIG. 1 in a sectional view;

FIG. 3 shows a modified embodiment of the blank according to FIG. 1 ;

FIG. 4 shows a further modified configuration of a dental arch blank forproviding an inventive dental prosthesis;

FIG. 5 shows a view of the prosthesis base blank showing indicatedpossible border lines of the interface to form the gingival margin;

FIG. 6 shows a further modified configuration of the dental arch blankaccording to FIG. 4 ;

FIG. 7 shows a finished dental prosthesis in one embodiment in asectional view;

FIG. 8 shows a further embodiment of a prosthesis according to FIG. 7 ;

FIG. 9 a shows further embodiments of inventive dental prostheses in thefinished state;

FIG. 9 b shows further embodiments of inventive dental prostheses in thefinished state;

FIG. 10 shows schematic illustrations of the blanks for providing aninventive prosthesis, also illustrating the tooth-colored blank;

FIG. 10 a shows schematic illustrations of the blanks for providing aninventive prosthesis, also illustrating the tooth-colored blank; and

FIG. 11 shows a schematic illustration of the blank according to FIG. 10wherein various dental arch sizes are indicated alternatively.

DETAILED DESCRIPTION

FIG. 1 shows a gum-colored blank 10 as a primary product of an inventivedental prosthesis in an embodiment in a perspective view. The basicstructure of the blank is disc-shaped and consists of gum-coloredmaterial which may also be referred to as gingival material. At itsupper side—in the illustration according to FIG. 1 —it comprises arecess 12 which is configured in a particular manner. Basically, therecess 12 extends in the form of a semicircle, that is to say in theshape of an arch. One of the characteristic features of the arch is thewave shape of the bottom side of the recess 12 which extends towards thearch. In the radial direction, that is to say from the center 17 of thearch towards the outside, that is to say towards the vestibular side, aradial shape is provided.

The arch 16 consists of alternating wave crests 18 and wave troughs 20.They extend isogonically such that the same wave crest exists at thesame angular position of the arch 16, and the same wave trough 20 existsat another consistent angular position.

It is apparent from FIG. 1 that the wave shape 14 of the arch 16deviates slightly from a sine shape. Indeed, the wave shape simulatesthe gingival margin and, in this respect, assumes some elements of acatenary and some elements of a sine shape.

The arch-shaped recess 12 is intended to receive a blank made oftooth-colored material which is shaped such that it fits the recess.Accordingly, the side of the blank made of tooth-colored material whichfaces the blank comprises a negative shape relative to the wave shape 14at the bottom of the recess 12. In this respect, the shape of thetooth-colored blank exactly matches the recess 12, possibly by leavingan adhesive gap having a thickness of between 50 μm and 150 μm.

Accordingly, the tooth-colored blank may be bonded into the recess 12 ofthe blank 10 easily.

Alternatively, it is also possible to produce a connection between theseblanks by polymerization.

By means of the joining operation, the blank 10 in turn obtains theshape of a circular disc altogether due to the filling of the recess 12,wherein in a way known per se an annular protrusion 24 is configuredcircumferentially and serves to be mounted in the workpiece holder of adental milling machine.

In this connection, it is provided to mount the blank 10 at an exactlypredetermined position by means of a positioning device which enables tomount the blank such that rotation is prevented. Thus, the blank whichhas possibly been machined partially may be removed for inspectionpurposes if necessary, and may then be reinserted in the correctposition.

According to the invention, after the two blanks have been connectedwith one another intensively in the described manner or in any othersuitable manner, the milling process which is predetermined by CAD/CAMis performed. The blank produced in this way makes it possible torealize any design of prostheses, that is to say prosthesis bases andteeth. The entire dental prosthesis may be produced in one go bymilling, and the gingival line 26 makes possible that the gingivalmargin provided in this way may not be differentiated from a naturalgingival margin at first glance.

Even if the recess 12 is described as a circular arc-shaped recess, itis to be understood that any other configurations of the shape arepossible. As is indicated in FIG. 1 the wave shape 14 is indeed loweredslightly in the vestibular/incisal area, and raised slightly in thevestibular/molar area, in accordance with the human gingival margin.

A possible distribution of the wave crests and wave troughs is apparentfrom the sectional view of the blank 10 illustrated in FIG. 2 . Theradial shape of the wave crests 18 or wave troughs 20, respectively,produces an asymmetric distribution of the wave crests and wave troughs,as can be seen from FIG. 2 .

The arch width of the arch 16—as viewed in the radial direction—isconsiderably larger than the vestibular/lingual or vestibular/palatalextension of a prosthesis tooth.

In this way, it is initially possible to determine any desired radialposition of the dental arch to be provided for by CAD. Thus, the size ofthe prosthesis, but also of the associated teeth, may be adapted to therequirements of the human jaw of the patient to a large extent. Due tothe radial shape, in case of smaller arches smaller teeth are producedautomatically as the distance between two crests 18 or between twotroughs 20 corresponds to the grid dimension of the teeth, respectively.

According to the invention, it is particularly favorable that theinserted teeth will not be separated even after the milling process butare present in the form of a dental arch. The interdental spaces arepreferably configured to be positioned deeply and the bridges ofmaterial between the individual teeth are shifted towards thelingual/palatal side. In this way, it is ensured that the opticalimpression of the inventive dental arch may not be differentiatedvirtually from a set of teeth with individual teeth.

Realizing the dental arch additionally allows for considerably increasedstrength.

This makes it possible to manage with teeth without tooth roots, that isto say teeth which are only held in position by means of the intensiveconnection with the gingival blank 10.

It is favorable to realize the recess 12, as is illustrated in FIG. 1and FIG. 2 , in order to precisely position the tooth blank relative tothe gingival blank.

In a modified embodiment, however, the arch 16 extends until the outercircumference of the blank 10, as is apparent from FIG. 3 . Thisembodiment, too, is suitable for forming a prosthesis base which fitsmany different sizes and shapes, wherein this embodiment also enablesslightly enlarged dental arches.

FIG. 3 shows a homogeneous distribution of the wave troughs 20 and thewave crests 18. In a still further modified embodiment it is provided torealize the wave crests and troughs to be narrower and smaller in thearea of the incisors, and accordingly to realize them broader and of alarger height in the area of the premolars and above all the molars.This accounts for the different tooth sizes and tooth widths along thecourse of a human set of teeth.

However, a human set of teeth is typically not exactly shaped like acircular arc, but recedes slightly in the incisal area, that is to sayin particular in the area of the teeth I, which have an almost planelabial surface, compared to a circular arc. Then, the radial shape ofthe crests 18 and troughs 20 automatically leads to smaller griddimensions thereat.

On the other hand, human upper jaw teeth II are typically slightlynarrower than the upper jaw teeth I. This can also be taken into accountby correspondingly adapting the width of the troughs and crests to therespective angular position, particularly in the case of upper jawprostheses.

In comparison, an even further modified dental arch blank 32 is apparentfrom FIG. 4 . The shape of the wave crests and wave troughs extendingradially and apparent from the FIG. 4 fits the prosthesis base blank 10in a manner true to shape, into the recess 12 disposed thereat.

In this embodiment the rays 28 extend towards a central point which isconsiderably lowered relative to the height of the gingival line. Inthis way, the rays 28 are caused to tilt relative to the horizontalwhich is favorable in particular embodiments and enables a bettermounting of the dental arch in the palatal/lingual region.

FIG. 5 shows an accordingly exposed, partially machined prosthesis baseblank 10 which illustrates the tilt of the radial line 28 described inconnection with FIG. 4 . Moreover, various border lines 27, 29 and 31are indicated in FIG. 5 which exemplify the milling line of theinterface 33 with respect to the dental arch blank 32 which is to beseen as the prosthesis gingival margin, in this respect.

Its position may be adjusted by the control device in a patient-specificmanner wherein in case of rather triangle-shaped jaw structures themesial region protrudes in accordance with the arrow 35, and the linestructure apart from that may be adapted to the requirements to a largeextent.

FIG. 6 shows how a dental arch 32 which is to be mounted in a recessedmanner in a circular arc recess in the partially machined prosthesisbase blank 10 may be built in layers.

It is apparent schematically that the dental arch blank 32 is built from5 layers 35 a, 35 b, 35 c, 35 d and 35 e which become increasingly darkand opaque towards the interface 33, corresponding to the dentin of ahuman tooth. It is to be understood that considerably more or also fewerlayers may be used.

Here, the layer transition 35 e-35 d follows the course of the rays,wave crests and wave troughs of the interface in an extenuated manner,while this characteristic becomes more and more extenuated towards thelayer 35 a. Examples of tooth shapes and sizes, 37 a and 37 b, are shownin dashed lines.

It is to be understood that here the two blanks are preferably eachproduced separate from one another by milling and are then joinedtogether and connected with one another intensively by adhesive bonding.During milling, the side flanks of the circular arc recesses to be seenthereat form stops of the inventive dental arch in the mesial/distaldirection likewise. This enables a particularly good anchorage of thedental arch as is particularly important with comparatively smallprostheses.

By milling off the outer side of the prosthesis base blank 10 theinventively particularly favorable gingival line between red and whitematerial can be made visible, in turn.

FIG. 7 shows how a finished prosthesis 30 may be configured incross-section.

It is apparent that the tooth-colored material 32 extends along theprosthesis base 10 produced in this way according to the gingivalmargin, but without perforating the gum-colored material 10, accordingto the natural dental arch. It is also apparent that in this preferredembodiment the material 32 is also held positively in the material 10 inthe radial direction.

FIG. 8 shows the finished dental prosthesis 34 with the aid of a wiremodel. By reference to the rearmost molar 36 as part of the inventivedental arch 38 it is apparent that it is embedded intensively ingingival material or connected with it intensively, respectively.

FIGS. 9 a and 9 b show prostheses produced accordingly in differentdirections of view in perspective.

FIG. 10 and FIG. 10 a show how the arch-shaped tooth-colored material32—still in the shape of a blank in this illustration—is inserted intothe recess 12 of the blank 10 and accommodated therein. The subsequentshape of the prosthesis 34 is illustrated schematically in FIG. 10 andFIG. 10 a , respectively.

FIG. 11 shows a section according to FIG. 10 wherein differentprostheses 34, 34 a and 34 b are illustrated with alternative sizes. Itis apparent that the blank 10 leaves sufficient free space for thelargest possible combinations of prosthesis bases and teeth both towardsthe occlusal/incisal side, that is to say in the region of the dentalarch 32, and in the central region towards the bottom, wherein it is tobe understood that the dimensions of the blank are known as boundaryconditions to the control device.

1. A one-piece or multi-piece prosthesis blank comprising a gum-coloredmaterial (10) and a tooth-colored material (32), the gum-colored and thetooth-colored material (10 and 32) being connected to each other atconnecting surfaces, wherein, viewed along the course of the connectingsurfaces, an interface between the materials has an undulating shapeand, viewed in a vestibular direction, has a radial shape, wherein thetooth-colored material (10) is configured to have several layerscomprising layers or regions near or adjacent the gum-colored materialconfigured to be darker and/or more opaque and regions distant from thegum-colored material configured to be brighter and/or more translucent.2. The one-piece or multi-piece prosthesis blank as claimed in claim 1,wherein interfaces between the layers near or adjacent the gum-coloredmaterial are undulating/radial, but less pronounced than the interfacebetween the gum-colored and the tooth colored material.
 3. The one-pieceor multi-piece prosthesis blank as claimed in claim 1, wherein theundulating surface comprises a wave shape (14), the wave shapecomprising wave troughs (20) and wave crests (18) expanded from a centerpoint in a radial manner, such that the wave troughs (20) and the wavecrests (18), viewed along the course of the connecting surfaces, exhibita consistent angular position in a radial manner.
 4. The one-piece ormulti-piece prosthesis blank as claimed in claim 1, wherein thetooth-colored material (32) is arranged in a shape of an arch forming atooth arch blank, wherein the width of the arch (16) is between 0.8 cmand 4 cm.
 5. The one-piece or multi-piece prosthesis blank as claimed inclaim 1, wherein the undulating shape (14) is configured substantiallyas a sine wave or as a catenary or as a hybrid form thereof comprisingan amplitude and/or period which is consistent or which changes orvaries along a course of the wave, catenary or hybrid form.
 6. Theone-piece or multi-piece prosthesis blank as claimed in claim 1, whereinthe undulating shape comprises wave troughs (20) and wave crests (18)characterized in that a height and/or width of the wave crests (18) ofthe tooth-colored material (32) increases from an inner point to anouter point, in a vestibular direction, and that an interface of theconnecting surfaces of the materials is configured in a catenary-shapedmanner.
 7. The one-piece or multi-piece prosthesis blank as claimed inclaim 1, formed into a finished prosthesis (34), wherein the gum-coloredmaterial forms a gingiva section and the tooth-colored material forms atooth or teeth, the tooth or teeth comprising tooth-colored wave crests,wherein every tooth-colored wave crest (18) follows an exposed edge ofthe tooth at a tooth neck with respect to the gingiva formed by thegum-colored material.
 8. The one-piece or multi-piece prosthesis blankas claimed in claim 1, formed into a finished prosthesis (34), wherein,with the finished prosthesis, the gum-colored material (10) is removed,at least partially to such an extent that, on a vestibular side, theparting line between the tooth-colored and gum-colored materials (32 and10) milled to be convex recedes as a gingival line (26), both withrespect to the remaining gum-colored and tooth-colored material (32). 9.The one-piece or multi-piece prosthesis blank as claimed in claim 1,wherein the gum-colored material (10) is configured as a disk, andwherein the gum-colored material (10) has an upper side that comprises apattern of radially extending wave lines, the pattern forming the exactnegative form of a corresponding pattern of the tooth-colored material(32).
 10. The one-piece or multi-piece prosthesis blank as claimed inclaim 1, wherein the tooth-colored material (32) is configured topositively match the gum-colored material and is receivable.
 11. Theone-piece or multi-piece prosthesis blank as claimed in claim 1, whereinthe tooth-colored material (32) is cast into a recess (12) of thegum-colored material, wherein the gum-colored material is provided witha wave-shaped profiling, and the tooth-colored material is polymerized.12. The one-piece or multi-piece prosthesis blank as claimed in claim 1,formed into a prosthesis comprising a gingival line formed at a pointwhere the gum-colored material meets the tooth-colored material, whereina spatial form of the prosthesis is determined by a CAD/CAM device, theCAD/CAM device comprising a control device which displaces the gingivalline (26) in the radial direction of the radial shape depending on thedesired tooth width, and also suggests and determines after userintervention the individual tooth shape, the rotation and/or theangulation of the teeth.
 13. The one-piece or multi-piece prosthesisblank as claimed in claim 12, wherein the control device determinesindividual tooth shapes, the rotation and/or the angulation of the teethand the shape of the prosthesis base which are produced together fromthe gum-colored material by milling.
 14. The one-piece or multi-pieceprosthesis blank as claimed in claim 1, wherein the disk or the elementmade of tooth-colored material (32) has an increasing height in adirection of the rays radially towards the outside, corresponding to alarger tooth height.
 15. A method of producing a dental prosthesiscomprising providing a one-piece or multi-piece prosthesis blank havinga gum-colored material and a tooth-colored material connected to eachother at connecting surfaces and comprising a gingival line at aninterface between the gum-colored and the tooth-colored materials, theinterface, when viewed along the connecting surfaces, has an undulatingshape and when viewed in a vestibular direction has a radial shape,using a CAD/CAM device to determine a spatial form of the prosthesis,the CAD/CAM device comprising a control device which displaces thegingival line in the radial direction of the radial shape depending onthe desired tooth width, and also suggests and determines after userintervention the individual tooth shape, the rotation and/or theangulation of the teeth in order to produce and finish the dentalprosthesis.
 16. The method of producing a dental prosthesis according toclaim 15, comprising supplying the CAD/CAM device with thepatient-specific data, where anatomically relevant points are marked andserve as reference points.
 17. The method of producing a dentalprosthesis according to claim 15, comprising obtaining thepatient-specific data from an intraoral 3D scan or an impression. 18.The method of producing a dental prosthesis according to claim 15,comprising using the CAD/CAM device to produce the prosthesis as avirtual prosthesis.
 19. The method of producing a dental prosthesisaccording to claim 18, comprising changing the virtual prosthesis by auser at the CAD/CAM device.
 20. The method of producing a dentalprosthesis according to claim 15, comprising using the CAD/CAM devicehaving a design function to construct and produce a vestibular borderline of the interface based on the patient-specific data.